How do you factor #-x^2+3x+4#?

1 Answer
Apr 5, 2018

Answer:

See a solution process below:

Explanation:

Because the #x^2# coefficient is #-1# we know the coefficient for one the #x# terms in the factor will also be #1# and the other a #-1#:

#(x )(-x )#

Because the constant is a positive and the coefficient for the #x# term is a positive, then the sign for the constants in the factors will both be positive::

#(x + )(-x + )#

Now we need to determine the factors which multiply to 4 and also add to 3:

#1 xx 4 = 4#; #-1 + 4 = 3# <- this IS the factor

#(x + 1)(-x + 4)#